Sobriety tests are normally administered by law enforcement authorities after a person suspected of intoxication has been arrested, e.g. for drunk driving. The suspect usually has no way of knowing, prior to driving, whether he is sufficiently intoxicated to be committing an illegal act by getting behind the wheel.
The problem arises from the fact that existing sobriety test equipment is generally expensive enough to prevent its widespread availability to the general public, and awkward enough to use to prevent its routine use by intoxicated persons without assistance. Typically, existing equipment requires parts to be assembled, and desiccant to be removed, before each test is conducted. Consequently, a need exists for a small, inexpensive one-piece sobriety testing device which can be made widely available in bars and stores; is simple enough to give reasonably accurate readings in the hands of users who are unskilled and sufficiently intoxicated to be concerned about their lack of sobriety; and can be discarded after use.